The results are... sequential nonsense. 1 day separation = 7141, 2 days = 14287, and so on. I know I'm missing something dumb, i just cannot for the life of me figure it out. Any help would be greatly appreciated.

But if you are going to include Holidays, I wouldn't use this method at all. I find it easier to set up a calendar table with one record for each day and then mark the days as either "open" or closed. An auto-enter calculation can mark weekend dates closed automatically and you can seven set up an actual calendar format with portals such that you can just click a button or enter a date into a global date field and run a script, to find and mark a given date as a holiday.

Then a relationship that matches to only dates with an "open" status in the date range specified can be used to count the number of days--which now counts all working days that are not also holidays.